Filter cigarette

ABSTRACT

A cigarette filter is surrounded by a wrapping paper, and the wrapping paper includes metal only on portion of a surface thereof, such that air can penetrate through the wrapping paper into the filter.

BACKGROUND OF THE INVENTION

The invention concerns a filter cigarette whose filter is surrounded bya filter wrapping paper which is enclosed by a tip layer, wherein aninterior of the filter wrapping paper is coated with metal, inparticular aluminum.

Development of cigarettes with reduced smoke constituents, in particularnicotine, condensate and carbon monoxide, has globally been drivenforward by statutory regulations, a higher level of consumer acceptanceand increased awareness of health.

Usually, cigarette papers which are highly permeable to air andburning-friendly are used for production of cigarettes with reducedsmoke constituents, and a cigarette filter has been additionally ventedby a perforated zone in a tip layer. Both technical measures dilute amain smoke flow by virtue of secondary air, and thereby reduce a levelof concentration of smoke constituents. Use of filter material with ahigh retention action and a high draw resistance also causes a reductionin smoke constituents, but encounters limitations in terms of acceptanceby consumers.

In the state of the art, DE 3038093 A1, WO 89/03183 A1 and CH 343865disclose cigarette filters in which metal is introduced into the filter.That, however, on the one hand involves a considerable increase inexpenditure in manufacture of filters, while on the other hand an effectachieved thereby is only very vaguely described with regard to itseffect.

SUMMARY OF THE INVENTION

Therefore, a basic starting point adopted by the invention is a filtercigarette whose filter is surrounded by a filter wrapping paper which isenclosed by a tip layer, wherein air can penetrate into the filterthrough the filter wrapping paper. In accordance with the invention acoating is applied only on a part of the filter wrapping paper so thatair can penetrate through the wrapping paper into the filter.

A metalization effect can be implemented by application in particleform, and/or by suitable application of flat patterns, to the wrappingpaper on a surface of the paper, but not by complete coating of thefilter wrapping paper. Surprisingly, partial coating of the filterwrapping paper with metal causes a selective reduction in carbonmonoxide content of a main smoke flow.

Further features and details of the present invention will be apparentfrom its specific description hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a filter wrapping paper according to the invention withaluminum strips, and

FIG. 2 shows a filter wrapping paper according to the invention with afinely distributed and highly porous aluminum layer.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1, aluminum strips have been applied to a commercially availablehighly porous paper for wrapping cigarette filters (Papierfabrik WattensGmbH, QNo 27400), with an air permeability of 6000 CU, by performing ahot foil process. A width of the porous paper was 26.5 mm and a width ofeach aluminum strip was 1 mm. A spacing between the strips was 1 mm.Filter rods for cigarettes were produced in a per se known manner from ausual industrial acetate cable measuring about 1000 m in length. FIG. 1shows a structure of such a filter rod comprising acetate cable 1,wrapping paper 2 and tip layer 3, while reference 4 denotes the aluminumstrips according to the invention.

Cigarettes are produced by machine, using these filter rods. Forcomparison purposes, cigarettes were produced on a basis of the samecomposition in terms of filter, cigarette paper and tobacco blend, butwithout previous zone-wise coating of a filter wrapping paper. Thecigarettes produced were smoked under standardized conditions in asmoking laboratory. With regard to cigarettes of the invention, smokeconstituents of a main smoke flow had a selectively and significantlylower carbon monoxide content, as shown in Table 1.

TABLE 1 Results of standardized smoking of cigarettes with (modified)and without (standard) aluminum strips 4 on the filter wrapping paper 2.Nicotine-free Draw Nicotine dry condensate number (mg/cig) (mg/cig) CO(mg/cig) Modified 8.42 (8.44) 0.61 (0.64) 8.37 (8.31) 9.04 (8.58) filterwrapping paper Standard 8.12 (8.24) 0.63 (0.64) 9.06 (9.08) 11.86(10.96) filter wrapping paper

The parenthesis show results of a second independent measurement series.

ÖZF: Österreichische Zigarettenfilter GmbH, Hainburg/Donau

FIG. 2 shows another embodiment according to the invention. Here, with astructure of the filter rod otherwise being the same with regard toacetate cable 1 and tip layer 3, filter wrapping paper 2 was coated withaluminum in a finely distributed form, but here aluminum layer 5 washighly porous. This kind of aluminum coating ensures that airpermeability of the filter wrapping paper is sufficiently maintained sothat, as also with the embodiment of FIG. 1, sufficient air can passlaterally into the cigarette filter.

For comparison purposes and to demonstrate action of the highly porousaluminum layer 5, besides the embodiment according to the invention asshown in FIG. 2, otherwise identical cigarette filters were producedwithout aluminum coating 5 on wrapping paper 2. These filter rods wereused to produce, by machine, otherwise equivalent cigarettes with andwithout the coating 5. The cigarettes produced therefore differ onlywith regard to presence of the coating 5. The cigarettes produced inthat way, as in the case of the embodiment of FIG. 1, were also smokedunder standardized conditions in a smoking laboratory. Measured smokeconstituents of a main smoke flow of cigarettes of this embodiment alsohave a selectively and significantly lower carbon monoxide content, andtherefore, have a similar effect as with the first embodiment. Table 2shows results of measurement of the same parameters as in Table 1, butin a comparison between cigarettes with a standard filter wrappingpaper, and cigarettes with filter wrapping paper 2 according to thesecond embodiment of the invention, which is coated with a finelydistributed highly porous aluminum layer 5.

TABLE 2 Results of standardized smoking of cigarettes with (modified)and without (standard) finely distributed highly porous aluminum coating5 on the filter wrapping paper 2. Nicotine-free Draw Nicotine drycondensate number (mg/cig) (mg/cig) CO (mg/cig) Modified filter 7.710.43 7.67 11.33 wrapping paper Standard filter 7.99 0.46 7.62 14.26wrapping paper

Clearly, the invention combines a known advantage of filter venting withan effect which is to be attributed to a metal coating. In this respect,the two embodiments show that an effect can be demonstrated,irrespective of a nature of the metal coating, as long as combination ofair permeability of filter wrapping paper and metal coating of thefilter wrapping paper is guaranteed. This makes it clear that theinvention is not limited to the illustrated embodiments, but includesall possible combinations of the embodiments shown herein and otherembodiments in accordance with combining a porous filter wrapping paperand a metal coating.

A physical or chemical mechanism to which this effect is to beattributed still remains to be investigated. A possible explanationwould be adsorption of carbon monoxide by the metal coating, whereas apurely catalytic action, because of a low temperature in the filter, isimprobable.

What is claimed is:
 1. A cigarette including a filter, wherein: saidfilter is surrounded by a wrapping paper; said wrapping paper includesmetal only on portion of a surface thereof, such that air can penetratethrough said wrapping paper into said filter; and said wrapping paper issurrounded by a tip layer.
 2. The cigarette according to claim 1,wherein said metal is on a surface of said wrapping paper that facessaid filter.
 3. The cigarette according to claim 2, wherein said metalcomprises aluminum.
 4. The cigarette according to claim 3, wherein saidmetal comprises longitudinally extending strips.
 5. The cigaretteaccording to claim 4, wherein said metal is finely distributed on saidwrapping paper in a highly porous form.
 6. The cigarette according toclaim 3, wherein said metal is finely distributed on said wrapping paperin a highly porous form.
 7. The cigarette according to claim 2, whereinsaid metal comprises longitudinally extending strips.
 8. The cigaretteaccording to claim 7, wherein said metal is finely distributed on saidwrapping paper in a highly porous form.
 9. The cigarette according toclaim 2, wherein said metal is finely distributed on said wrapping paperin a highly porous form.
 10. A cigarette filter, wherein: said filter issurrounded by a wrapping paper; said wrapping paper includes metal onlyon portion of a surface thereof, such that air can penetrate throughsaid wrapping paper into said filter; and said wrapping paper issurrounded by a tip layer.
 11. The cigarette filter according to claim10, wherein said metal is on a surface of said wrapping paper that facessaid filter.
 12. The cigarette filter according to claim 11, whereinsaid metal comprises aluminum.
 13. The cigarette filter according toclaim 12, wherein said metal comprises longitudinally extending strips.14. The cigarette filter according to claim 13, wherein said metal isfinely distributed on said wrapping paper in a highly porous form. 15.The cigarette filter according to claim 12, wherein said metal is finelydistributed on said wrapping paper in a highly porous form.
 16. Thecigarette filter according to claim 11, wherein said metal compriseslongitudinally extending strips.
 17. The cigarette filter according toclaim 16, wherein said metal is finely distributed on said wrappingpaper in a highly porous form.
 18. The cigarette filter according toclaim 11, wherein said metal is finely distributed on said wrappingpaper in a highly porous form.